The present invention relates to a collimator array including a plurality of collimators.
A typical optical collimating apparatus includes two opposed collimator arrays. The first collimator array has collimator lenses to convert the light emitted from optical fibers to collimated beams of light. The second collimator array converges and couples the collimated beams of light in an optical fiber with a collimator lens. Gradient index rod lenses having predetermined gradient indexes in the radial direction are employed as the collimator lenses of the first and second collimator arrays.
Optical devices, such as an optical filter, an optical isolator, and an optical switch, are arranged between the first and second collimator arrays. The optical collimating apparatus affects the light transmitted from the optical fibers of the first collimator array in a predetermined manner and couples the light in the corresponding optical fibers of the second collimator array.
FIG. 1 is a schematic diagram of a collimator array 100 used in a prior art optical collimating device. The collimator array 100 includes a plurality of single fiber collimators that are positioned by V-grooves formed on a base plate. Each single fiber collimator includes a gradient index rod lens 1, a single mode optical fiber 2, a capillary 3 for holding the optical fiber 2, and a glass tube 4 for holding the capillary 3 and the rod lens 1. The core axis of the optical fiber 2 coincides with the optical axis of the rod lens 1.
The collimator array 100 of the prior art collimator array 100 has the problems described below.
(1) The rod lens 1 must be positioned to adjust the angle of the beam emitted from the rod lens 1 of each collimator. To align each collimator, the collimator must be rotated as shown by the arrow in FIG. 1 in accordance with data of the light emission angle while detecting the beam direction. In this case, the detection of the beam direction of each collimator is difficult. Further, it takes time to align each collimator so that the emission angle of the collimator beam is the same as that of other collimator beams.
(2) To shorten the time for aligning the collimators, the beam emission angles of a plurality of collimators may be monitored in real time. However, this requires high technology and expensive equipment.
(3) When the beam emission position of each collimator must be corrected, further adjustment of the collimator is necessary.
It is an object of the present invention to provide a collimator array that facilitates the alignment of the optical axis.
To achieve the above object, the present invention provides a collimator array for use with a light source. The collimator array includes a plurality of collimators, each including a lens and an optical fiber optically coupled to the lens with the lenses of the collimators arranged so that the optical axes of the lenses are parallel to one another. In each collimator, a core axis of the optical fiber is positioned relative to the optical axis of the lens so that when receiving light from the light source, an optical beam is emitted from a predetermined position on an exit end surface of the lens at a predetermined angle.
A further aspect of the present invention is a method for manufacturing a collimator array. The collimator array includes a plurality of collimators, each having a lens and an optical fiber optically coupled to the lens. The method includes the step of preparing a first lens block and a second lens block with the first lens block including a plurality of first lens holding grooves and a plurality of first lens block positioning grooves, and the second lens block including a plurality of second lens holding grooves, each opposed to an associated one of the first lens holding grooves, and a plurality of second lens block positioning grooves, each opposed to an associated one of the first lens block positioning grooves. The method further includes the step of preparing a first fiber block and a second fiber block with the first fiber block including a plurality of first fiber holding grooves and a plurality of first fiber block positioning grooves, and the second fiber block including a plurality of second fiber holding grooves, each opposed to an associated one of the first fiber holding grooves, and a plurality of second fiber block positioning grooves, each opposed to an associated one of the first fiber block positioning grooves. Further, the method includes the steps of arranging the lenses of the collimators in the second lens holding grooves, arranging the optical fibers of the collimators in the second fiber holding grooves, engaging a plurality of guide pins with the second lens block positioning grooves and the second fiber block positioning grooves, placing the first lens block on the second lens block so that the first lens holding grooves are opposed to the second lens holding grooves with the lenses located in between, and placing the first fiber block on the second fiber block so that the first fiber holding grooves are opposed to the second fiber holding grooves with the optical fibers located in between.
Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.